Master cylinder valve



May 6, 1941. s. SCHNELL MASTER CYLINDER VALVE Filed Dec. s, 1939 8 5 mmm/ u u w y 382.;)

ATTONEY Patented May 6, 1941 .rri cs 2,240,52 Mesme, CYLINDER VALVE teve Schnell, Overland, Mo., asignor to Wagner St. Louis, Mo., a corpora- Electric Corporation,

tion of Delaware Appiicaticn December 16, 1939, Serial No. 309572 10 Claims. (Ci. 251 27) Mylinvention relates to valve mechanism and more particularly to an improved valve Construction for use in a master cylinder device for developing fluid pressure such as, for example, the master cylinder device shown by my'co-pending application Serial No. 274540, filed May 19, 1939.

One of the objects of my' invention is to provide an improved valve mechanism of the type in which the cooperating elements, comprising a yieldable scaling member and an engageable non- 'esilient member, are so associated with each other that the valve will be capable of efciently confining high fluid pressures.

Another object of my invention is to so construct a valve mechanism embodying a yieldable scaling member that said member will not be cut or damaged by a movable non-resilient member.

Still a further object of my inventionis to produce an improved yieldable scaling member for a valve.

Other objects of my invention will become apparent from the following description taken in connection with the accompanying drawing in which Figure 1 is a cross-sectional View of a portion of a master cylinder device having in- -corporated therein a valve structure embodying `my invention; Figure 2 is a cros's-sectional view of a modified Construction; and Figura 3 is a cross-sectional view of another modified construction.

Referring to Figura 1, the particular master cylinder device in which my improved: valve structure is incorporated comprises a casing I fixed to a convenient support and forming a reservoir 2 for fluid. Within the casing is a cylinder member 3 mounted at its front end in a guide 4 and at its rear end in a cylindrical extension 5 for reciprocable movement. A stop 6 limits the rearward movement and a packing cup 'I 'seals the cylinder and reservoir. As shown, the forward portion of the cylinder member 3 which is mounted in the guide is in the form of a cylindrical extension 8 of reduced internal diameter and the' end surface thereof cooperates with a plug 9 to form a valve li] to control communication between the reservoir 2 and the cylinder member. The plug has an outlet passage ll which is connected by a Conduit !2 to a fiuid motor for actuating by any desired devce, as for example, a vehicle brake.

The cylinder member at the extension 8 is provided with a partition !3 having a passage l l for permitting communication between the interier of the extension and the main portion of the cylinder member. Within the cylinder is a piston !5 having mounted on its end a scaling cup IE. The skirt of the piston is split to form resilient portions ll which provide rction between the cylinder and the piston. The piston is actuated by a piston rod 18 and a cooperating spring (not shown) normally biases the 'piston to its retraoted position as shown wherein it abuts a stop !9 on the cylinder and also positions the cylinder against its stop 6.

When the piston rod IS is initially moved, the friction between the cup and the cylinder wall and the friction between the skirt of the piston and cylinder wall will cause the cylinder member to move with the piston and to a position to close valve lil. This will cut ofi communication between the reservoir and the interier of the extension 8. Continued movement of the piston rod will now cause the piston to move relatively to the cylinder member and thereby place the fluid in the cylinder under pressure and force it out the outlet ll to actuate the fiuid motor connected to the conduit !2. The valve member lil is maintained in closed position by the frictional drag between the cup and piston and the cylinder and also by the difierential force between the forces acting on the partition due to the difference in areas acted upon by the fluid pressure in the main portion of the cylinder member and in the extension 8. This dierential force increases with increasing fluid pressure caused by forward movement of the piston in the cylinder member 3. j

When the piston is retracted, the pressure in the cylinder member will drop and the friction between both the piston and piston cup and the cylinder wall will move the cylinder member rearward and open valve m, thereby releasing the fluid under pressure acting on the fluid motor. The parts assume the positions shown in Figure 1 when the piston is fully retracted. When valve ID is open, expansion and contraction of the fluid is permitted. Also, if during rapid retractile movement of the piston sub-atmospherie pressure is created in the cylinder, fluid from the reservoir'will readily flow into the cylinder through the open valve.

In the type of master cylinder device just described, it is necessary to have the valve lil so constructed that it will hold high pressures, will not be cut by the end of the extension 8 and the plug, nd 'will not be damaged by the release of the fluid under high pressure when the valve is 'initially opened.

In accordance with my invention the plug 9 is provided with an extension 20 through which extends the outlet ll and this extension at its inner end has a fiange ZI. The plug is also provided with an axial extending annular fiange 22 in spaced surrounding relation to the extension 26 and the outer end thereof has a beveled surface 23 which is adapted to cooperate with a beveled surface 24 on the end of the extension 8 of the cylinder member 3. .A scaling member 25 made of rubber or like material is mounted upon the extension 20 and cooperates with the end of tially engaged by the flat end surface 29 on the extension 8 of the cylinder member 3 when it is moved to close the valve; To assist in holding the sealing member in position the flange 22 may be under cut as shown at 30 and the outer surface of' the body portionvis formed to a flt.. If it is desired a retaining ring SI may be mounted on the outer end of the lip 21 and held in position by flange 21.7

With the valve mechanism incorporated in the master cylinder device in the manner described fluid under pressure will be effectively sealed when it is closed and the valve will be capabl'e of a iong eicient life. When the cylinder member 3 moves forwardiy the surface 29 will engage the rib 28 and compress it until the beveled surfaces 23 and 24 engage. 'Since the edge of the scaling member lies slightly back of the bevel surface 23 there isno danger of it being pushed into the space between the beveled surfaces as they approach each other. This will now confine the scaling member. The fluid pressure i'n the extension 8 whichacts thereonwill force. the lip 21 tightly against the surface of the extension 20 and the body portion 23 against the surface or the plug and the flange 22 thereby preventng fluid under pressure from creeping around the scaling member. Also the fluid pressure acting on the surface of the sealing member between the ridge 28 and the lip 21 will compress this portion of'the scaling member andcause the rid'ge to engage the surface 29 with additional pressure.

"When the cylinder member 3 is retracted and the valve opened the ridge willbecome disengaged from the surface 29 and during this disengagement there is no danger ofthe rib being forced between the beveled 'surfaces because of it's' V-shape cross section. Also no fluid can get behind the body portion of the cup and force it in between the beveled surfaces. Thus a subsequent closing of the valve will therefore not cut the scaling member. In order to insure that the beveled surfaces will have full contact at all points the extension B has slight 'play in the guide fl as shown.

Referring to the modified structure shown in Figure 2., a similar valve Construction is shown which does not require the cooperatingi beveled surfacesor the plug and the cylindrical extension 8. The plug 9 is the same as the one described 'except that the flange 22' is not provided with a beveled surface. The scaling member 25' is mount'ed on the extension 20 and has a fai'rly thiok body portion 23'. surrounding a part" of the body portion of' reduced diameter's 'a' ring 3-2. This ring projects slightlybeyond the edge of the-flange22-' and is adapted tobe-engaged by the fiat end surface 33 on theend of the extension 8' of the reciprocable cylinder member-3. The ridge 28 on the body` of' the sealing member. projectsbeyond the ring as shown for. engagement: with the surface 33 prior to its conta'ctwiththe ring..

2 When. the cylinder member 3 isi moved forward the surface 33 will first engage the relatively sharp edge of the ridge 28 and begin to compress it. Next the surface 33 will engage the ring 32 and press it into the portion of the body of the scaling member at its back. *The movement of the cylinder member 3 end of fiange 22' and under these conditions the scaling' member is so conflned that there is no possibility of high fluid pressure forcing it into any Cracks where it can be cut or become damaged. The fluid pressure acting on the yieldable material of the sealing member will also compress it and cause it to have pressure engagep ment with the surfaces it Contacts. The compressed portion back of the ring 32 will maintain the ring' against the surface 33 at all points. When the cylinder member 3 is'retracted the V- shape cross section' of* the ridge will insure that highfluid pressures being released will not force any portion of' the sealing member into the space between the ring 'and'surface 33.

In the modified construction shown in Figure 3 the scaling member 25* is the same as shown in Figure 1-. The flange 22"' on the plug 9 is provided with spaced axially extending lugs 34 which serve as guides for the reduced end 35 on the extension 8 which is of such diameter to be snugly received in the fiange 22". i

When thevalve is open as shown fluid is to` flow between the lugs3 member ismoved forwardly ,the fiat end surface 36- on the' extension 8 engages the ridge 28 and begins` to compress it and the body of the sealing member. Next the reduced end passes the end of the fiange 22" and thus connes the sealing member. The forward movement of the free cylinder member 3 is stopped by engagement of' the lugs 34 with the' shoulder 31 formed by the reduced end 35.

Being aware of the possibility of other modiflcations in the' particular structures herein described without departing from the fundamental' principles of my invention, 'I do not intend that movable member; and an annular scaling member positioned in said recess and provided with a ribfor engagement with the end surface of the movable member when it is 'moved toward the fixed member, said fixed member and movab-le member having associatedfltherewith cooperating means which' become operative after the movable member has engaged and compressed the yieldable member to thereby confine the yieldable member in the reoess and prevent fluid pressurein the* annuiar movable member from causing any' portion of the yieldabie member to be forced out of the recess. i i

2. In a fluid pressureapparatus providedwith a member having anoutl-et` and an annuar recess in concentric relatior' to the outlet, an annuar member, said members having relative movement, an annuiar yieldable sealing member positioned in the reoess' and having an an- 'nular rib'adapted to' beehgaged and ccmpressed by the' end of the annular member when the members are moved relatively toward eachother, and' means comprising; cooperating surfaces for confining the scaling member and preventing't is stopped when it engages the When the cylinder i from being forced outwardly beyond its periphery by fluid pressure acting thereon, said surfaces being moved into cooperating relation after the annular member has engaged and compressed the rib.

3. In a fluid pressure app aratus, a fixed member, an annular movable member, said fixed member being provided with an annular recess, an annular yieldable sealing member positioned in said recess and having an annular rib of general V-shaped cross section which is `adapted to be engageable by a flat surface on the movable member when moved toward the fixed member, said yieldable member also being provided with a portion forming :an annular lip engaging the inner annular surface of the recess and being exposed to fluid at all times, and means providing surfaces on the movable member and the fixed member which are capable of being brought into cooperative relationship after the surface on the movable member engages the rib and thus confine the sealing member in the recess.

4. In fluid pressure apparatus provided with a fixed member having an outlet and a recess surrounding the outlet, and annular movable member, a yieldable sealing member positioned in the recess and having an annular rib projecting outward beyond the outer wall of the recess, and a rigid ring imbedded in the forward portion of the periphery of the sealing member and projecting outwardly beyond the outer wall of the recess but lying back of the edge of the rib whereby the end of the annular member when moved toward the fixed member will first engage and compress the rib of the sealing member and then engage the ring and compress the portion of the sealing member which lies in back thereof.

5. In fluid pressure apparatus provided With a fixed member having an outlet and a recess surrounding the outlet, an annular movable member having a flat end surface, a yieldable sealing member positioned in the recess and having an inner sealing lip engaging the Inner wall of the recess and a concentric annular rib projecting outward beyond the outer wall of the recess, and a rigld ring imbedded in the forward portion of the periphery of the sealing member and projecting outwardly beyond the outer wall of the recess but lying back of the edge of the rib Whereby the flat end surface of the anmlar member when moved toward the fixed member for engagement therewith will first engage and compress the rib of the sealing member and then engage the ring and compress the portion of the sealing member which lies in back thereof.

6. A valve seat of yieldable material for a fluid pressure apparatus comprising an annular body portion provided with an axially extending annular tapered flange forming a lip which is adapted to be exposed to fluid pressure on its outer surface and an annular rib in spaced surrounding rel ation to the flange and of general V-shaped cross section.

'7. A valve seat of yieldable material for a fluid pressure apparatus comprising an annular body portion having a flat end surface, an axially extending annular tapered flange projecting from the inner part of the body portion and on the end opposite the flat end surface and adapted to be exposed to fluid pressure on its outer surface, and an annular rib also on the same end as the flange and in spaced surrounding relation to said flange, said rib being of a general V-shaped cross section and of less axial length than the 8. In fluid pressure app aratus, a fixed member having a cylindrical extension forming an outlet passage and a recess surrounding the extension, an annular movable member in spaced surrounding relation to the extension, an annular yieldable sealing member positioned in the recess and having an inner axial flange exposed to fluid pressure and engaging the cylindrical extension, said sealing member :also being provided With an outer annular rib surrounding the flange and adapted to 'be engaged and compressed by the movable member when moved toward the fixed member, and means on the portion of the fixed member surrounding the sealing member and on the annular movable member capable of cooperation with each other to conflne the rib and prevent it from being forced outwardly by fluid pressure ac ting on the sealing member when the annular member is moved toward the fixed member, said cooperating means assuming the conning relationship after the movable member has engaged and compressed the rib.

9. In fluid pressure apparatus, a fixed member having a cylindrical extension forming an outlet passage, a recess surrounding the extension and an annul'ar beveled surface adjacent the recess, an annular movable member in spaced surrounding reiation to the extension andprovided with a flat end surface and an annular beveled surface, an annular yieldable sealing member positioned in the recess and having an inner axial flange exposed to fluid pressure and engaging the cylindrical extension, said sealing member also being provided with an annular rib' surrounding the flange and engageable by the flat end surface of the movable member when it is moved toward the fixed member, said beveled surfaces on the fixed and movable members being capab le of cooperating engagement to confine the rib and prevent it from being forced outwardly by fluid pressure acting on the sealing member after the flat end surface has engaged the rib.

10. In fluid pressure apparatus, a fixed member having a cylindrical extension forming an outlet passage, a recess surrounding the extension and an annular beveled surface adjacent the recess, an annular movable member in spaced surrounding relation to the extension and provided with a flat end surface, said annular member being of a size to snugly telescope within the outer wall of the recess, an annular yieldable sealing member positioned in the recess and having an inner axial flange exposed to fluid pressure and engaging the cylindrical extension and also an annular rib surrounding the flange for engagement by the flat end surface of the movable member when it is 'moved toward the fixed member, said rib being so related to the outer wall of the recess that the end of the annular movable member will engage and compress it prior to said movable member assuming its telescoping relation with the outer wall of the recess to thereby confine the sealing member.

STEVE SCHNELL. 

